Jakob Herschend

Disease-induced assemblage of a plant-beneficial bacterial consortium

Disease suppressive soils typically develop after a disease outbreak due to the subsequent assembly of protective microbiota in the rhizosphere. The role of the plant immune system in the assemblage of a protective rhizosphere microbiome is largely unknown. In this study, we demonstrate that Arabidopsis thaliana specifically promotes three bacterial species in the rhizosphere upon foliar defense activation by the downy mildew pathogen Hyaloperonospora arabidopsidis. The promoted bacteria were isolated and found to interact synergistically in biofilm formation in vitro. Although separately these bacteria did not affect the plant significantly, together they induced systemic resistance against downy mildew and promoted growth of the plant. Moreover, we show that the soil-mediated legacy of a primary population of downy mildew infected plants confers enhanced protection against this pathogen in a second population of plants growing in the same soil. Together our results indicate that plants can adjust their root microbiome upon pathogen infection and specifically recruit a group of disease resistance-inducing and growth-promoting beneficial microbes, therewith potentially maximizing the chance of survival of their offspring that will grow in the same soil.

Genome Sequence of Kocuria varians G6 Isolated from a Slaughterhouse in Denmark

ABSTRACT We report here the first draft genome sequence of Kocuria varians G6, which was isolated from a meat chopper at a small slaughterhouse in Denmark. The 2.90-Mb genome sequence consists of 95 contigs and contains 2,518 predicted protein-coding genes.

Draft Genome Sequences of Two Kocuria Isolates, K. salsicia G1 and K. rhizophila G2, Isolated from a Slaughterhouse in Denmark

ABSTRACT We report here the draft genome sequences of Kocuria salsicia G1 and Kocuria rhizophila G2, which were isolated from a meat chopper at a small slaughterhouse in Denmark. The two annotated genomes are 2.99 Mb and 2.88 Mb in size, respectively.

Enhanced bacterial mutualism through an evolved biofilm phenotype

Microbial communities primarily consist of multiple species that affect one another’s fitness both directly and indirectly. This study showed that the cocultivation of Paenibacillus amylolyticus and Xanthomonas retroflexus exhibited facultative mutualistic interactions in a static environment, during the course of which a new adapted phenotypic variant of X. retroflexus appeared. Although the emergence of this variant was not directly linked to the presence of P. amylolyticus, its establishment in the coculture enhanced the productivity of both species due to mutations that stimulated biofilm formation. The mutations were detected in genes encoding a diguanylate cyclase predicted to synthesise cyclic-di-GMP. Examinations of the biofilm formed in cocultures of P. amylolyticus and the new variant of X. retroflexus revealed a distinct spatial organisation: P. amylolyticus only resided in biofilms in association with X. retroflexus and occupied the outer layers. The X. retroflexus variant therefore facilitated increased P. amylolyticus growth as it produced more biofilm biomass. The increase in X. retroflexus biomass was thus not at the expense of P. amylolyticus, demonstrating that interspecies interactions can shape diversification in a mutualistic coculture and reinforce these interactions, ultimately resulting in enhanced communal performance.

Enrichment and characterization of an environmental microbial consortium displaying efficient keratinolytic activity

Keratin refers to a group of insoluble and recalcitrant protein materials. Slaughterhouses produce large amount of keratinous byproducts, which are either disposed or poorly valorized through costly thermochemical processes for animal feed formulation. Learning from nature, keratinolytic microbial consortia stand as a cost-efficient and environmental friendly way to valorize this recalcitrant resource. Directed selection was applied to enrich soil-born microbial consortia, using sequential batch cultivations in keratin medium, while measuring enzymes activity and monitoring consortia compositions via 16S rRNA gene amplicon sequencing. A promising microbial consortium KMCG6, featuring mainly members of Bacteroidetes and Proteobacteria, was obtained. It possessed keratinolytic activity with <25% residual substrate remaining, which also displayed a high degradation reproducibility level after long-term cryopreservation. This work represents an advance in the field of α-keratin degradation with potential for practical applications.

Genome Sequence of Arthrobacter antarcticus Strain W2, Isolated from a Slaughterhouse

We report the draft genome sequence ofArthrobacter antarcticusstrain W2, which was isolated from a wall of a small slaughterhouse in Denmark. The 4.43-Mb genome sequence was assembled into 170 contigs.

Draft Genome Assembly of Two Pseudoclavibacter helvolus Strains, G8 and W3, Isolated from Slaughterhouse Environments

ABSTRACT We report the draft genome sequences of two Pseudoclavibacter helvolus strains. Strain G8 was isolated from a meat chopper and strain W3 isolated from the wall of a small slaughterhouse in Denmark. The two annotated genomes are 3.91 Mb and 4.00 Mb in size, respectively.

Genome Sequence of Kocuria palustris Strain W4

ABSTRACT We report the 3.09 Mb draft genome sequence of Kocuria palustris W4, isolated from a slaughterhouse in Denmark.

Genome Sequence of Psychrobacter cibarius Strain W1

ABSTRACT Here, we report the draft genome sequence of Psychrobacter cibarius strain W1, which was isolated at a slaughterhouse in Denmark. The 3.63-Mb genome sequence was assembled into 241 contigs.